Take your set out and lay the clubs out in order against a wall with the sole of each club sitting flat on the ground. You'll notice that when laying flat across the sole, the tops of the shafts form a straight line along the wall. Effectively, your 3 iron is the same length as your pitching wedge. If you have a top line set, each club is made to swing, weigh, feel exactly the same as any other in the set. You'll notice the 3 iron head sits a little further from the wall than the pitching wedge. That's the only difference between the two. At address the ball is a little further away from you. If you can hit a pitching wedge, you can hit a three iron, from near the exact same set up you use to hit a pitching wedge. Except that your wrists are slightly less pronated, but not enough the average person would even notice, and maybe you widen your stance just a bit.

Pull the 9 off the wall and set up with it. Without changing anything, switch out the 9 for the 4. Literally that's all you're doing when you hit a 4 iron. Where you go wrong, is at some point, usually around the 5 iron, you change your set up. You reach out further, stand more upright, widen your stance way too much. Which is totally unnecessary, and the reason why you can't hit any club longer than the next one down.

Next time you play, when you determine the shot calls for a long iron, you do this: Go to your bag and locate the 4 or 3 or whatever it is. Only look at the number on the bottom long enough to put your hand on it and yank it out of your golf bag. Then don't look at it again. Look at the hole, look at the ball look at anything but the club. Never look at it until you are already in rough position next to the ball. As you get into your stance put the head behind the ball only looking at the head of the club. The last thing you want to do is hold the club out in front of you, look down the shaft and say, "Oh my god... it's like 5 feet long!" Ignore the urge to do so. Tell yourself as you walk up it's just a 7 iron, and set up for a 7 iron shot. Because it is a 7 iron. It sits what, like an inch and half further away from you. You probably wouldn't even notice if you had a 7 iron an inch and a half too far away from your feet.

When you finally break that mental block that's telling you your 3 and 4 are somehow different from the rest of your clubs. You'll never have trouble again. Whatever you do, stop looking at it!